Coated chemically-active substance and method of making same.



UNITED STATES I PATENT OFFICE.-

IjREDEBIO J. SMITH, OF ELIZABETH, NEW JERSEY, ASSIGNOR TO WILLIAM II. BOWKER, OF BOSTON, MASSACHUSETTS.

COATED CHEMlCALLY-ACTIVE SUBSTANCE AND METHOD OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 714,960, dated December 2, 1902. Application filed June 5,1901. Renewed May 9, 1902- Serial No. 106.636. (No specimens.)

To all whom it may concern: Be it known that I, FREDERIC J. SMITH, a citizen of the United States, residing at Elizabeth, in the county-of Union and State of New 7 Jersey, have invented certain new and useful Improvements in Coated Chemically-Active Substances and Methods of Making the Same, of which the following is a specification. Y

My invention has for its object the treatment of chemically-active substances whereby .when' in comminuted form their particles shall be isolated from or protected against the chemical efiect of any surrounding or contiguous medium, as the atmosphere, active -.chemicals, &c., and also whereby they may be mechanically combined with other substances, producing mixtures wherein the action or chemical reactions of the comminuted substances may be retarded-or postponed until the time and under the circumstances dc sired.- One class of substances to :be thus treated may be described as those which are strongly basic, .as the oxid'and hydroxids of-v the alkali and alkaline-earth group of met- Thomas slag, so called, anhydrous carbonate of soda, &c.

-My improved .method of treating substances when in comminuted form consists,

, broadly, incoating or surrounding the comminuted particles with a soluble fused salt,

which, while inert relatively to the comminuted. particle and impervious to or uninfluenced by certain external and surrounding agencies, shall be susceptible of being dis- 0 solved when desired in water in such a man- 4 ner as to permit the comminuted particles thereafter to act alone or under the influence of surrounding or adjacent media or to react with such surrounding or adjacent media.

detail the preferredmethod of employing my process in the treatment of comminuted caustic or burnt lime, such being taken as a typ-' ical case. 5o The caustic lime having been comminuted to the desired fineness, preferably so as to I will now proceed to describe somewhat in-.

pass through a forty-mesh sieve, a quantity of a soluble fusible salt, preferably nitrate of soda, is placed in a suitable heating device and its temperature is raised to the meltingpoint. In the case of nitrate of soda when thus melted it will be in the form of a limpid liquid. To this liquid I then add with con-' stant stirring a quantity of com minuted lime.

'I have foundin practice that in carrying out my invention with reference to the production of protected comminuted lime to be employed in a mechanical mixture with comm-i-r nuted blue vitriol to form the well-known ,Bordeaux mixture in dry form four parts of nitrate of soda should be mixed with three parts, by weights, of the comminuted lime. The heating and stirring are-continued, care being taken not to overheat until a uniform plastic or semifiuid mass results. i It should be noted that if. the mixture be overheated a chemical reaction will ensue, which will destroy the caustic properties of the lime and decompose the nitrate of soda. After the heated mass has become sufficiently mixed it is withdrawn-from the source of heat in any suitable manner and spread upon a suitable surfaces'uch as a shallow sheetiron pan, upon' which it is allowed to cool.

When cool, the mass will form a hard brittle 8o cake, wherein the particlestof comminuted lime will be found to be practically hermetically sealed or incased in a skin or envelop of nitrate of soda, these in turn being held 7 together by the same medium, forming a mass which maybe broken, crushed, or ground to any desired size. One of the purposes for which I wish to make use of this coated lime is the preparation of a commercial dry Bordeaux mixture which shall possess all the 0 properties of the freshly prepared article. The usual method of preparing the Bordeaux mixture now practiced is to make a water solution of blue vitriol; also, a separate solution of caustic or slaked lime and water, commonly known as milk of lime, and to then mix the two together, after which the mixture is readyfor use.

In the making of Bor deaux mixture it is necessary to have the lime present in its highly-caustic state-i e., freshly 1o burnt and water-slaked-in order that it may quickly react on the blue vitriol, and I have discovered that by coating the caustic or burnt lime in comminnted form, as above described, its original basic properties are preserved and that it can be safely mixed with comminnted blue vitriol without any material reactions until it is desired to use the mixture, when it is only necessary to add waterand'the proper reaction will take place. Iuconsequence a mixture is thus produced in which copper 'hydroxid and sulfate of lime will exist in the same condition as in the Bordeaux mixture as ordinarily freshly prepared and in which the precipitated compounds will be found suflici'ently free from gritty particles that they may be conveniently applied as a spray through a nozzle or in any other manner. It has also been long recognized that substances strongly basic--sucli as burnt lime, (CaO,) carbonate of potash, &c., are desirable substances to apply to the soil; but it has been impossible to apply them in a powdered state and preserve at the same time their full causticity, which fact partic ularly applies to lime. Oomminuted burnt lime and comminnted carbonate of potash treated according to my invention can be readily transported and applied to the soil broadcast or by machines without loss of their valuable basic properties when the moisture of the soil will dissolve the coating and the desired reactions take place. It has also been observed that valuable fertilizing mixtures could be made with burnt lime or carbonate of potash if these materials could' be incorporated in such mixtures without the loss of their basic properties or reacting on the other substances with which they are mixed. By my invention common burnt lime or carbonate of potash can be com minuted and coated as above described and then readily mixed with nitrogenous substances, such as dried blood and sulfate of ammonia, both carrying am monia without'causing any reaction. whereby the ammonia would be liberated, as would be the case if these basic substances above referred to were mixed with these ingredients withoutanycoating, and similarly these same alkalies coated as above described could be mixed with other potash salts and water-soluble phosphates without producing any serious reaction or reversion. The preparations would vary with the requirements of diiferent soils or different crops.

. I have discovered that by my'invention coated alkalies in a comminnted form may be used in the preparation of mixed fertilizers and sold and applied in powderediorm, which has never been done successfully before. In

coating should have a point of fusion lower than that of the substance to be coated. I claim- 1. The improvement in the art of treating a chemically-active substance for the purpose of regulating its time and manner of chemical action and reaction which consists in commiuuting said substance, mixing the commiuuted particles thereof with a fused salt, soluble in water and not reacting with the substance to be treated, and allowing the mixture to cool.

2. As a new product a chemically-active substance in comminnted form, the particles of which are coated with a salt applied in a fused state to them and subsequently cooled,

said salt not reacting chemically with the coated substance and being soluble in water.

3. As a new product, a basic substance in comminnted form, the particles of which are coated with a salt applied in a fused state to them, and subsequently cooled, said salt not reacting chemically with the coated substance and being soluble in water.

4. As a new product, a basic substance in comminnted form, the particles of which are coated with a salt applied in a fused state to them, and subsequently cooled, said salt being soluble in water-not reacting with the coated substance, and inert when mixed with blue vitriol.

5. As a new product, a basic substance in comminnted form, the particles of which are coated with a salt applied in a fused state to them, and subsequently cooled, said salt not reactingv with the coated substance being soluble in water, and inert when mixed with such fertilizing ingredients as nitrogenous matters, potash salts and soluble phosphates.

In testimony whereof I have hereunto subscribed by name this lstth'day of May, 1901.

FREDERIC J. SMI'lII.

\Vitnesses:

HENRY J. MILLER, HANNAH N. 1 MiLLu'u. 

